Leaver Lies – the WTO rules will be what the UK will use post Brexit: The default for trade for most of the world is the WTO but only if you are a member. Remember if any leaver lies about how the UK falls back to the WTO then explain to them that the UK is part of the WTO via the EU so the UK would have to become a WTO member in its own right through a new set of “schedules” (WTO speak for the terms and conditions of membership). The UK membership is not carried forward automatically.
So the UK joins the WTO ? Now the scary part; Every one of the other 162 WTO nations has to agree to what the UK tables as its new schedules. It isn’t a vote but everyone has a consensus. So these kind of WTO agreements take a long time. The Marrakesh agreement took 12 years (with then 124 countries).
You can guarantee that when the UK is getting closer to Brexecution day then all the old disputes that the UK has got hidden in the closet of the past couple of hundred years of the British empire with other states will be dusted off and put onto the table of any WTO schedule negotiation by these other states and the UK will just have to take it and compromise.